The prevalence of alcohol abuse and alcoholism among different ethnic groups varies widely.. Certain tribes of Native Americans have very high rates of alcohol abuse when compared to Caucasian, African American, and Asian American subjects living in the same geographic areas. These ethnic differences in rates of alcoholism are thought to reflect a combination of sociocuItural and biological factors. Within the biological realm, several preliminary studies provide evidence to suggest that certain electrophysiological variables (ERPs and EEGs) may be good markers of genetic predisposition to alcoholism. Few studies, however, have evaluated whether ethnic and/ or racial diversities exist in electrophysiological markers of alcoholism risk. Recent data do suggest that there is genetic diversity in biologic sensitivity to alcohol. The source of the differences in alcohol sensitivity are not well understood, but presumably result, in part, from genetic differences in metabolic factors, i.e., genetic polymorphisms of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), as well as inborn differences in CNS "reactivity." The overall objective of the proposed studies is to extend our previous investigations, which evaluated biologic reactivity to alcohol and placebo challenge in Caucasian sons of alcoholics, Asian American men, and Native American men. Our preliminary studies suggest that Native American men have a qualitatively different response to alcohol than Caucasian and Asian American men. We believe that this diversity in response to alcohol may, in part, account for their increased risk for the development of alcoholism. In order to explore this further, in new sets of studies, both Native American men and women ages 18-25 will be tested for biologic reactivity to alcohol and placebo using a modification of the same alcohol challenge protocol from our previous studies. In addition, behavioral and electrophysiological data will be collected from Native American boys and girls between the ages of 8-11 in order to determine whether specific risk markers might be present in young boys and girls prior to any alcohol exposure. These studies have the potential to verify whether Native Americans have any specific biological or behavioral factors that may help to explain the high risk for alcoholism within the tribes evaluated. The identification of such variables may potentially be useful in the development of specific prevention and treatment programs for this population as well as other Native American tribes.